Pneumatically operated valve means and fuel control system utilizing the same

ABSTRACT

A pneumatically operated valve means having a housing means provided with an inlet separated from an outlet by a valve seat, the outlet having an orifice through which the entire fuel flow from the inlet must pass when the valve seat is open. A pneumatically operated valve member is carried by the housing for opening and closing the valve seat. A metering pin has one end cooperating with the orifice for controlling fuel flow therethrough and is operatively interconnected to the valve member to be moved thereby for providing different levels of fuel flow through the housing.

[151 3,672,400 [451 June27,1972

nited States Paton Scott [54] PNEUMATICALLY OPERATED VALVE Xl n4 um 7 33,048,274 8/1962 Lundeen........................... MEANS AND FUELCONTROL SYSTEM 3372:; 3:33; fi gf c roy........ UTILIZING THE SAME2,610,063 9/1952 Faucheux [72] Inventor: Douglas R. Scott, E1khart,1nd.3,236,261 2/1966 Morgan................

[73] Assignee: Robertshaw Controls Company Richmond, Va.

n, Jr., Robert L. Marben and Can- [22] Filed: July 27, 1970 [21] App].No.:

, 7 levels of fuel flow through the housing. 1,254,599 1/1918Irwin..;........................,....,.251/122 X 3,201,937 8/1965McKee.......................... 251/122 X 18 C1aims,5DrawingFiguresPATENTEDJUW m2 3, 672,400

sum 3 0r 5 FIG. 3

INVENTOR. DOUGLAS R. SCOTT W, W $7M HIS ATTORNEYS PMENTEnJuw m2 3,72,400

saw u or 5 FIG. 4

INVENTOR. DOUGLAS R. SCOTT HIS ATTORNEYS PATENTEUJUHN r972 3,672,400

SHEET s or 5 INVENTOR. DOUGLAS R. SCOTT HIS ATTORNEYS PNEUMA'IICALLYOPERATED VALVE MEANS AND FUEL CONTROL SYSTEM UTILIZING THE SAME Itiswell known from theaforementioned patent application I that a fuelburning apparatus, such as a clothes dryer or the like, can be providedwherein the flow of fuel to the main burner .means thereof is controlledby a pneumatic control system wherein pneumatically operated valve meansmust receive a pneumatic signal in order to interconnect a fuel sourcewith the main burner means. 7

It is a feature of this invention to provide an improved pneumaticallyoperated valve means for such a fuel control system or the like. I

In particular, one embodiment of this invention provides a housing meanshaving an inlet separated from-an outlet by a valve seat. The outlet hasan orifice through which the entire fuel flow from the inlet must passto the main burner means when the valve seat is opened. A pneumaticallyoperated valve member is carried by the housing means for opening andclosing the valve seat. A metering pin has one end cooperating with theorifice for controlling fuel flow therethrough and is operativelyinterconnected to the valve memberby lost motion means whereby when thevalve member is moved to a certain open position thereof, the meteringpin remains in a normal position relative to the orifice for one levelor rate of fuel flow to main burner means. However, further movement ofthe valve member to another open position thereof causes the lost motionmeans to be taken up and move the metering pin 4 to a new operatingposition thereof to provide a greater'flow In order to fully understandthe operation and utility of the pneumatically operated valve means ofthis invention, the entire fuel control system utilizing such apneumatically operated valve means will first be described.

Referring now to FIG. 1, the improved control system of this inventionis generallyindicated by the reference numeral andis utilized for.controlling the operation of a clothes dryer, generally indicated bythe reference numeral 11, having a mainbumer means 12 adapted to beinterconnected to a fuel source manifold 13 by a pair of pneumaticallyoperated valve means 14 and 14 in a manner hereinafter described.

reference to the accompanying drawing forming a part thereof andwherein:

FIG. Us a schematic view illustrating the improved control system ofthis invention.

FIG. 2 is an enlarged, fragmentary view of the pneumatically operatedlogic units of the control system of FIG. 1 with the logic units beingillustrated in cross section.

FIG. 3 is a cross-sectional view illustrating the improved pneumaticallyoperated valve means of this invention with the valve means being in aclosed position thereof.

FIG. 4 is a view similar to FIG. 3 and illustrates the pneumaticallyoperated valve means in a fully open position thereof.

FIG. 5 is a view similar to FIG. 3 and illustrates another embodiment ofthe pneumatically operated valve means of this invention.

While the various features of this invention are hereinafter describedand illustrated as being particularly adapted to pneumatically controlthe operation of a domestic clothes dryer or the like, it is to beunderstood that the various features of this invention can be utilizedsingly or in any combination thereof to provide control means for othertypes of apparatus as desired.

Therefore, this invention is not to be limited to only the embodimentsillustrated in the drawings, because the drawings are merely utilized toillustrate one of the widevariety of uses of this invention. 1

The apparatus 11 includes an electric motor 15 which rotates theclothes-receiving drum (not shown) of the apparatus 11 during the entirecycle of operation of the apparatus 11in a conventional manner, theelectric motor 15 being adapted to be interconnected across two powersource leads L and L in amanner hereinafter described.

The electric motor 15 is adapted to drive an eccentric cam 16 that isinterconnected to its output shaft 17 as long as the electric motor 15is energized whereby the eccentric cam 16 will continuously move apiston rod arrangement 18 to operate a vacuum pump means 19 so as toprovide a continuous vacuum source for the system 10 of this inventionas long as the electric motor 15 is energized, the vacuum pump means 19having its inlet 20 interconnected to a conduit means 21.

The power source lead I. is interconnected to one side 22 of theelectric motor 15 by a lead 23. The other power source lead 1.. isinterconnected by a lead 24 to a conventional timer operated switchblade 25 that has its contact 26 cooperable with a fixed contact 27 thatis interconnected by a lead 28 to a dryer door operated switch blade 29.The dryer door operated switch blade 29 has a contact 30 cooperable witha contact 31 that is interconnected by a lead 32 to the other side 33 ofthe electric motor 15.

Therefore, it can be seen that in order for the electric motor 15 to beplaced across the power source leads L and l. for the electric motor 15to be energized, not only must the dryer door be disposed in its closedposition to close and hold the switch blade 29 against the contact 31,but also the housewife or the like must manually set the cycle timermeans (not shown) of the control system 10 so that the same is in an oncondition to hold the switch blade 25 against the contact 27 for apreset time period after the lapse of which the timer cycle means willautomatically open the switch blade 25 away from the contact 27 toterminate the operation of the control system 10in a conventionalmanner.

The pneumatically operated valve means 14 and 14' for interconnectingthe fuel source conduit 13 to the main burner means 12 of the apparatus11 are substantially identical in construction and operation and whileone such valve means could properly control the on-off condition of themain burner means 12, the use of two such valve means merely provides asafety factor so that if one of the valve means fails, the other valvemeans will still perform its function.

As illustrated in FIG. 1, the pneumatically operated valve means 14 and14 comprise a housing means 35 having valve seats 36 and 36' thatinterconnect a fuel source inlet 37 to a fuel source outlet 38, thevalve seats 36 and 36' being opened and closed by valve members 39 and39' that are moved between their opened and closed positions by vacuumoperated actuators that are generally indicated by the referencenumerals 40 and 40. The vacuum operated actuators 40 and 40' areschematically illustrated in FIGS. 1 and 2 and thereby comprisecup-shaped housing members 41 and 41' having their open ends 42 and 42closed by flexible diaphragms 43 and 43' that are interconnected to thevalve members 39 and 39 by tying means 44 and 44 in a conventionalmanner whereby the flexible diaphragms 43 and 43' cooperate with thehousings 41 and 41' to define chambers 45 and 45' therebetween.Compression springs 46 and 46' are the valve seats 36 and 36' to preventany flow of fuel to the main burner means 12. However, when the vacuumsource 19 is interconnected to the chambers 45 and 45' in a mannerhereinafter described to evacuate the chambers 45 and 45', the pressuredifferential acting across the diaphragms 43 and 43' moves thediaphragms 43 and 43' in opposition to the force of the compressionsprings 46 and 46' to move the valve members 39 and 39' to their openpositions so that the fuel source 13 will be interconnected to the mainburner means 12 as long as the pneumatically operated actuators 40 and40' are in their actuated condition.

The ignition means for the main burner means 12 comprises an ignitioncoil 47 having one side 48 thereof interconnected by a lead 49 to thelead 24 through a door operated switch 29', similar to door switch 29,so that the side 48 of the ignition coil 47 is always interconnected tothe power source lead L when the dryer door is closed. The other side 50of the ignition coil 47 is interconnected by a lead 51 to a switch blade52 that has a contact 53 cooperable with a contact 54 that isinterconnected to the power source lead L by a lead 55.

A vacuum operated actuator 56 controls the switch blade 52 andcomprisesa cup-shaped housing 57 having its open end 58 closed by aflexible diaphragm 59 that is interconnected to the switch blade 52 by asuitable tying means 60, the flexible diaphragm 59 cooperating with thehousing 57 to define a chamber 61 therebetween that receives acompression spring 62 that normally tends to urge the flexible diaphragm59 upwardly to hold the switch blade 52 out of contact with the contact54 and thereby maintain the ignition coil 47 in its de-energizedcondition. However, when the chamber 61 of the actuator 56 isinterconnected to the vacuum source 19 in a manner hereinafterdescribed, the resulting pressure differential acting across thediaphragm 59 moves the diaphragm 59 downwardly in opposition to theforce of the compression spring 62 to place the switch blade 52 intocontact with the contact 54 so as to place the ignition coil 47 acrossthe power source leads L and L When the ignition coil 47 is placedacross the power source leads L and L by the vacuum operated actuator 56in a manner hereinafter described, the ignition coil 47 subsequentlyheats up to a temperature that will be sufficient for igniting fuelissuing from the main burner means 12 in a conventional igniting manner.

An ignition coil temperature sensing means 63 is provided for the systemand comprises a bimetal member 64 that is interconnected to a valvemember 65 by a typing means 66, the valve member 65 being disposed in ahousing means 67 having a valve seat 68 fluidly interconnecting aconduit 69 to a conduit 70. When the bimetal member 64 senses atemperature of the ignition coil 47 below a temperature sufficient forigniting fuel issuing from the main burner means 12, the bimetal member64 is in such a condition that the same maintains the valve member 65away from the valve seat 68 and against a valve seat 68' that leads tothe atmosphere so as to fluidly interconnect the conduits 69 and 70together. However, when the ignition coil 47 reaches an ignitiontemperature, the bimetal member 64 warps in such a manner that the samemoves the valve member 65 against the valve seat 68 to terminate thefluid connection between the conduits 69 and 70 and opens the valve seat68 so that atmosphere is interconnected to the conduit 70 for a purposehereinafter described. In addition, when the main burner means 12 isoperating, the bimetal member 64 also senses the flames at the mainburner means 12 so that the bimetal member 64 will maintain the valvemember 65 in its closed position against the valve seat 68 as long asfuel is burning at the main burner means 12.

Another temperature sensing device 71 is provided for the control system10 and is adapted to sense the temperature effect of the main burnermeans 12. The temperature sensing means 71 comprises a bimetal member 72that is interconnected to a valve member 73 by a tying means 74, thevalve member 73 being disposed in a housing means 75 to open and close avalve seat 76 thereof that is adapted to fluidly interconnect theatmosphere with the interior of the housing 75 when the valve seat 76 isopen. However, when the valve seat 76 is closed, the housing 75, inefi'ect, interconnects the conduit 21 to the conduit 69 of the ignitiontemperature sensing means 63.

As long as the temperature effect of the burner means 12 of theapparatus 11 is below a predetermined temperature effect setting of thesensing means 71, the bimetal member 72 maintains the valve member 73against the valve seat 76 to, in effect, fluidly interconnect theconduits 21 and 69 together whereby if the electric motor 15 isenergized, the vacuum source 19 will be interconnected to the conduit69. However, when the temperature sensing means 71 senses a temperatureeffect of the burner means 12 above the set temperature effect settingof the thermostatic means 71, the bimetal member 72 warps in a manner tomove the valve member 73 away from the valve seat 76 and, thus, ineffect, disconnects the vacuum source 19 from the conduit 69 as theatmosphere is now interconnected to the conduit 69 through the openedvalve seat 76 for a purpose hereinafter described. Of course, it is tobe understood that the sensing device 71 could be manually adjustablefor temperature selection purposes by the housewife or the like or couldbe factory set for an optimum drying temperature for the apparatus 1 1.

The conduit 69 is interconnected by a conduit 77 to a port means 78 of apneumatically operated logic memory unit 79 later to be described, theconduit 77 also being fluidly interconnected to a conduit 80 that leadsto a port means 81 of a pneumatically operated logic nand" unit 82 ofthis invention. The conduit 80 has a restriction 83 therein intermediatethe port means 81 of the logic nand unit 82 and the conduit 77.

The conduit 70 leading from the ignition temperature sensing means 63 isinterconnected to another port means 85 of the logic nand unit 82 aswell as to a conduit 86 that is interconnected to one side 87 of a checkvalve 88, the conduit 70 having a restriction means 89 therein inadvance of the conduit 86.

The check valve 88 comprises a housing means 90 having a valve seat 91adapted to be opened and closed by a valve member 92, the valve seat 91being adapted to interconnect the conduit 86 at the side 87 thereof tothe other side 93 of the check valve 88 that leads to a conduit 94. Thevalve member 92 normally seats against the valve seat 91 to preventfluid communication between the conduits 86 and 94 so that when theconduit 70 is interconnected to the vacuum source 19 by the valve means63 and 71 being disposed in the positions of FIG. 1, the vacuum source19 opens the valve member 92 away from the valve seat 91 so as to beinterconnected to the conduit 94.

The conduit 94 is fluidly interconnected to a conduit 95 that has oneend 96 thereof interconnected to a port means 97 of the logic "memoryunit 79 while the other end 98 of the conduit 95 is interconnected toanother port means 99 of the logic memory unit 79.

The conduit 95 is fluidly interconnected to a conduit 101 that leads toa port means 102 of the logic nand unit 82, the logic nand" unit havinganother port means 103 thereof fluidly interconnected to a conduit means104 that is fluidly interconnected to branch conduit means 105 and 105that are respectively fluidly interconnected to the chambers 45 and 45'of the vacuum actuators 40 and 40. The branch conduits 105 and 105'respectively have restrictions 107 and 107' therein.

The conduit 104 intermediate the actuators 40 and 40 and the nand" unit82 is interconnected to the atmosphere by a controlled bleed means for apurpose hereinafter described. However, the controlled bleed means 100interconnects the conduit 104 to the atmosphere at a controlled ratethat is less than the effective rate of fluid interconnection providedby the restriction 83 in the conduit 77 as will be apparent hereinafter.

The conduit 70 leading from the ignition temperature sensing means 63 isfluidly interconnected to a conduit 106 that is fluidly interconnectedto the chamber 61 of the actuator 56.

A remaining port means 108 of the logic nand" unit 82 is interconnectedto the atmosphere through a filter 108 and a port means 109 of the logicmemory unit 79 is interconnected to the atmosphere.

The remaining port means 110 of the memory unit 79 is interconnected bya conduit 110 to the conduit 70 intermediate the restriction 89 and thesensor 63 for a purpose hereinafter described and to the atmospherethrough a restriction 100', the conduit 110' having a one-way checkvalve 88 similar to the check valve 88 whereby like parts are indicatedby like reference numerals followed by a prime mark.

As previously stated, the control system is so constructed and arrangedthat the ignition coil 47 for the burner means 12 must be firstenergized to a temperature thereof that will be sufficient for ignitingfuel issuing from the burner means 12 each time before the actuators 40and 40 will be actuated to simultaneously move the valve members 39 and39' from their closed positions to their open positions to cause fuel toissue from the main burner means 12.

Thus, since both temperature sensing devices 63 and 71 are normallydisposed in the positions illustrated in FIG. 1 when the control system10 is initially turned on by the housewife or the like setting the timercycle means in its on position to close the switch blade 25 against thecontact 27, the thus ener gized electric motor will operate the vacuumpump 19 and since the temperature effect of the apparatus 11 is belowthe temperature effect setting of the thermostatic device 71, the vacuumpump 19 is adapted to evacuate the conduit 69 through the closed housing75 as well as to evacuate the conduit means 70 and 77 leadingrespectively to the logic memory" unit 79 and logic nand unit 82.

The logic nand unit 82 will now receive a pneumatic signal at the portmeans 102 thereof from the memory unit 79 as well as a pneumatic signalat the port means 85 thereof as long as the valve member 65 of theignition temperature sensing means 63 is in its open position from thevalve seat 68 and is closed against the valve seat 68' whereby the nandunit will be in a de-activated condition to prevent the vacuum source 19from being interconnected to the conduit 104 so that the valve means 14and 14 remain in their closed positions to prevent fuel from reachingthe main burner means 12. However, after the ignition coil 47 reachesits ignition condition, the valve means 65 closes against the valve seat68 and opens the valve seat 68' so as to terminate the pneumatic signalto the port means 85 of the nand unit 82 whereby the nand" unit 82 willnow be activated to a condition thereof to interconnect the vacuumsource 19 to the conduit 104 so that the actuators 40 and 40' will beevacuated to open the valve members 39 and 39' so that fuel can issuefrom the burner means 12 and be ignited by the ignition means 47.

Accordingly, the logic units 79 and 82 always require that the valvemember 65 must first be in its open position away from the valve seat 68and then be moved to a closed position against the valve seat 68 aftereach closing of the main valve means 14 and 14' before the main valvemeans 14 and 14' can be again opened, the valve member 65 only closingagainst the valve seat 68 after an open condition thereof by theignition coil 47 being energized to a temperature suitable for ignitingfuel that is to subsequently issue from the main burner means 12.

The details of the logic units 79 and 82 for accomplishing the abovefunction will now be described in detail whereby reference is now madeto FIG. 2.

As illustrated in FIG. 2, the logic units 79 and 82 are substantiallyidentical in construction whereby only the particular details of thelogic memory unit 79 will now be described and like parts of the logicnand unit 82 will be indicated by the same reference numerals followedby the reference letter A." In this manner, it will be appreciated thatthe logic units of this invention can be made from the same parts in asimple and effective manner while producing different logic functions aswill be apparent hereinafter so that the cost of the control system 10of this invention is relatively small when considering the costs ofprior known electrical and pneumatic control systems.

As illustrated in FIG. 2, the logic memory unit 79 com prises twohousing parts 111 and 112 suitably secured together to hold two annularmembers 113 and 114 between the opposed and respective inner end wallmeans 115 and 116 thereof. A flexible, one-piece diaphragm member 117 isdisposed in the housing means 111 and 112 and has an inter mediate orlarge central outwardly directed diaphragm portion 1 18 provided with anouter peripheral portion 1 19 that is secured and sealed between theannular members 113 and 114. An outboard smaller spaced diaphragmportion 120 of the diaphragm member 117 has its outer periphery 121secured and sealed between the housing member 111 and the annular member113 to define a chamber 122 between the diaphragm portion 120 and theend wall means 115 of the housing member 1 11 while cooperating with thelarger central diaphragm portion 118 to define a chamber 123 between thediaphragm portions 118 and 120. An opposed smaller outboard spaceddiaphragm portion 124 of the diaphragm member 117 has its outerperiphery 125 secured and sealed between the annular member 114 and thehousing member 112 to define a chamber 126 between the diaphragm portion124 and the end wall means 116 of the housing member 112 whilecooperating with the central diaphragm portion 118 to define a chamber127 between the diaphragm portions 118 and 124.

. The diaphragm member 117 has a bore 128 interrupting the end 129thereof so as to receive a compression spring 130 that has one endbearing against the end wall means 116 of the housing member 112 and theother end thereof bearing against the diaphragm member 117 to normallyurge the diaphragm portion 120 against a frustoconical valve seat 131that projects inwardly from the end wall means 115 of the housing member111 into the chamber 122. The valve seat means 131 of the logic memoryunit 79 is interconnected to the port means 78 thereof that leads to theconduit 77 whereas the valve seat means 131A of the nand unit 82 isinterconnected to the port means 81 that leads to the conduit 80.

The diaphragm member 117 has a passage means 132 passing through thediaphragm portion 120 in offset relation to the valve seat 131 so as toalways fluidly interconnect the chambers 122 and 126 together, thepassage 132 also being in offset relation to a frustoconical valve seat133 that projects inwardly from the end wall means 115 of the housingmember 112 and is received in the bore 128 of the diaphragm member 117to be opened and closed by the end wall 134 of the diaphragm member 117that defines the closed end of the bore 128 and forms part of theeffective surface of the diaphragm portion 124 that defines the chamber126. The valve seat 133 of the logic memory unit 79 is interconnected tothe port 110 which leads to the conduit 110' and the valve seat 133A ofthe logic nand" unit 82 is interconnected to the port means 108 thatleads to the atmosphere.

The port means 78 and 99 of the housing member 111 and the port means110 of the housing member 112 can comprise outwardly extending tubularnipples that can be effectively telescoped into flexible conduit meansto fluidly interconnect the same to such conduit means, such nippleextensions con taining suitable air filtering means 134. In theembodiment illustrated in FIG. 2, the nipple port means 99 and 78 of thelogic memory unit 79 are fluidly interconnected respectively to theconduits 98 and 70 whereas the nipple port means 81 and 103 of the logicnand unit 82 are respectively interconnected to the conduits 80 and 104.

The annular member 114 carries the port means 97 in the form of a nippleextension projecting out of an opening means 135 in the housing member112 and the port means 109 comprises a nipple extension of the annularmember 113 projecting out of an opening means 136 of the housing member1 11. The nipple port means 97 of the logic memory unit 79 is invnvnv vV terconnected to the end 96 of the conduit member 95 and the nippleport means 109 is interconnected to the atmosphere whereas thecorresponding nipple port means 102 and 85 of the logic "nand unit 82are respectively interconnected to the conduits 101 and 70.

Accordingly, it can be seen that the chamber 122 of the logic memory"unit 79 is always interconnected to the port means 99 and, thus, to theend 98 of the conduit 95 whereas the port means 78 and, thus, theconduit 77 is adapted to be interconnected to the chamber 122 when thediaphragm member 117 opens the valve seat 131. The atmosphere port means109 is always interconnected to the chamber 123. The chamber 127 isalways interconnected by the port means 97 to the end 96 of the conduitmeans 95. As previously stated, the chamber 126 is always interconnectedto the chamber 122 by the passage means 132 and is adapted to beinterconnected to the atmosphere or effectively blocked from theatmosphere at the port means 1 10 except for the controlled rateprovided by the bleed restriction 100' when the diaphragm member 117opens the valve seat 133 depending on whether the valve 88' is open orclosed as will be apparent hereinafter.

In regard to the logic nand" unit 82, the chamber 122A thereof is alwaysinterconnected by the port means 103 to the conduit 104 and is adaptedto be interconnected to the port means 81 and, thus, to the conduit 80when the diaphragm member 117A opens the valve seat 131A, the chamber122A always being interconnected to the chamber 126A by the passagemeans 132A in the diaphragm member 117A. The chamber 123A is alwaysinterconnected by the port means 85 to the conduit 70. The chamber 127Ais always interconnected by the port means 102 to the conduit 101. Thechamber 126A, while always being interconnected to the chamber 122A bythe passage means 132A in the diaphragm member 117A, is adapted to beinterconnected to the atmosphere at the port 108 when the diaphragmmember 117A opens the valve seat 133A.

The operation of the control system 10 of this invention will now bedescribed.

Assuming that the dryer door is in its closed position to hold theswitch blades 29 and 29' in their closed positions, the housewife or thelike sets the timer selector means for operating the dryer 11 for apredetermined length of time whereby the timer mechanism closes andholds the switch blade 25 against the contact 27 and will maintain theswitch blade 25 against the contact 27 during the entire cycle ofoperation of the dryer 11 so that at the conclusion of such time period,the timer means will automatically open the blade 25 away from thecontact 27 to terminate the operation of the apparatus 11.

With the switch blade 25 now moved to its closed position against thecontact 27, it can be seen that the electric motor is placed across thepower source leads L and L so that the electric motor 15 willcontinuously rotate the laundry receiving drum to tumble the clothesinan atmosphere to be heated by the burner means 12 for drying of thelaundry or the like. As the output shaft 17 of the motor 15 iscontinuously rotating, the same through the eccentric cam 16reciprocates suitable pumping mechanism of the vacuum pump 19 tocontinuously provide a vacuum source for the control system 10.

At the initial operation of the control system 10, not only is theignition coil 47 not at an ignition temperature, but also thetemperature effect of the apparatus 11 is below the temperature effectsetting of the thermostatic means 71 whereby both valvemembers and 73are in the position as illustrated in FIG. 1 so that the vacuum source19 is not only interconnected to the vacuum operated actuator 56 toevacuate the chamber 61 thereof and close the switch blade 52 againstthe contact 54 to place the ignition coil 47 across the power sourceleads L and 1. but also the vacuum source 19 is interconnected by theconduits 77 and 80 to the valve seats 131 and 131A of the "memory" unit79 and nand" unit 82, which valve seats 131 and 131A are normally closedby the diaphragm members 117 and 117A due to the force of the respectivecompression springs 130 and 130A, and by the conduit means 70 to thechambers 127 and 122 of the "memory unit 79 and the chamber 123A of thenand unit 82. The vacuum in the conduits 70 and 110' causes the checkvalve 88 to close so that the open valve seat 133 of the "memory unit 79is efiectively blocked from the atmosphere as the bleed 100' does notefiect evacuation of chamber 126.

In particular, since the conduit 70 is interconnected to the inlet 20 ofthe vacuum pump 19 by the positioned valve members 65 and 73, the vacuumpump 19 can evacuate the chamber 123A of the nand" unit 82 to maintainthe diaphragm member 117A thereof in its de-activated and seatingposition against the valve seat 131A so that the vacuum source in theconduit leading to the valve seat 131A cannot reach the actuators 40 and40' to open the valve means 14 and 14'.

Also, since the conduit 86 is now being evacuated, the check valve 88opens whereas the check valve 88' closes so that the conduit can beevacuated whereby the end 96 thereof evacuates the chamber 127 of thememory unit 79 so that the resulting pressure differential acting acrossthe large central diaphragm portion 118 causes the diaphragm member 117to move upwardly in FIG. 2 in opposition to the force of the compressionspring to its activated position to open the valve seat 131.

However, before the evacuation of the chamber 127 of the "memory" unit79 can efiect the switching of the diaphragm member 117 upwardly in FIG.2, the vacuum source 19 now being interconnected to the chamber 126 bythe way of conduit 95, chamber 122 and diaphragm passage 132 to chamber126, assists in the complete evacuation of the chamber 122 so that whenthe diaphragm member 117 does switch to its up position in FIG. 2, noatmospheric pressure is permitted to pass out into the conduit 95 and,thus, slow down or prevent the setting of the memory unit 79 in its on"position.

With the valve seat 131 now being opened by the activated "memory" unit79, the vacuum source 19 is interconnected by the conduit 77 through therestriction means 83 to the chamber 122 of the memory" unit 79 so thatthe conduit 101 effectively leading from the chamber 122 of the memoryunit 79 is evacuated to evacuate the chamber 127A of the nand" unit 82.

With the chamber 127A of the "nand unit 82 now being evacuated, it canbe seen that as long as the valve member 65 of the ignition temperaturesensing means 63 is in its seated position against the valve seat 68',the opposing chamber 123A of the "nand" unit 82 is also evacuated sothat an equal vacuum condition exists across the central diaphragmportion 118A of the diaphragm member 117A of the nand unit 82 so thatthe compression spring 130A maintains the diaphragm member 117A in itsup or de-activated position in FIG. 2 to maintain the valve seat 131Athereof closed and the chamber 122A thereof that leads to the chambers45 and 45' of the actuators 40 and 40' of the valve means 14 and 14interconnected to the atmosphere thrOugh the passage means 132A of thediaphragm member 117A and the open valve seat 133A whereby the vAlvemembers 14 and 14 cannot be opened to interconnect the fuel source 13 tothe main burner means 12 as long as a vacuum signal is directed to thechamber 123A by the ignition sensing means 63.

However, when the energized ignition coil 47 subsequently heats up toignition condition, the sensing member 64 warps downwardly in FIG. 1 toopen the valve seat 68' and close the valve member 65 against the valveseat 68 and thereby disconnect the vacuum source 19 from the conduit 70which begins to return to atmospheric condition by the opened valve seat68' so that not only is the chamber 61 of the actuator 56 returned toatmospheric condition to open the switch blade 52 away from the contact54 and de-energize the ignition coil 47, but also the chamber 123A ofthe nand" unit 82 returns to atmospheric condition whereby the resultingpressure diffcrentiai acting across the diaphragm portion 118A of thediaphragm member 117A of the nand" unit 82 causes the diaphragm member117A to move downwardly in H0. 2 in 9 opposition to the force of thecompression spring 130A to its activated position to not only open thevalve seat 131A to the chamber 122A, but also to close the valve seat133A from the chamber 126A.

In this manner, since the valve member 73 of the temperature effectsensing means 71 in its open condition, the vacuum source 19, in effect,is interconnected to the chambers 45 and 45 of the actuators 40 and 40to move the valve members 39 and 39' to their open position so that thefuel source 13 is now interconnected to the main burner means 12 and isignited by the ignition coil 47.

As previously stated, when the valve member 65 of the ignitiontemperature sensing means 63 ismoved to its closed position against thevalve seat68 to permit the now opened valve seat 68' to return theconduit 70 to atmospheric condition to terminate the vacuum signal tothe chamber 123A of the nand unit 82 so as to activate the same, thecheck valve 88 closes so that such return of air into the conduit 70cannot reach the conduit 94 whereby the diaphragm member 117 of thememory unit 79 remains in its actuated condition wherein the valve seat131 is in its open condition and the valve seat 133 is in its closedcondition so that a continuous vacuum signal is directed from the.chamber 122 to the chamber 127A of the nand unit to maintain the nandunit in its activated position for maintaining the valve means 14 and14' in their open condition, the restriction 83 providing a greater flowthan the controlled bleed means 100 in the conduit 104 so that the valvemeans 14 and 14' remain open. A holding circuit is provided for thememory unit from the vacuum source 19 to the chamber 122 of the memory"unit 79 and by means of the conduit 95 to the chamber 127 to maintainthe diaphragm member 117 in its up or activated position. Also, thereturn of air into the conduit 70 causes the check valve 88 to openwhereby atmosphere is at the closed valve seat 133 of unit 79.

Thus, since flames now exist at the main burner means 12, thetemperature sensing means 63 will maintain the valve member 65 closedagainst the valve seat 68 so that the burner means 12 will continue tooperate unless the temperature effect being produced by the burner means12 exceeds the predetermined temperature effect setting of thethermostat means 71.

lf the temperature effect of the burner means 12 exceeds the setting ofthe thermostat 71, the temperature sensing member 72 will move the valvemember 73 away from the valve seat 76 to effectively disconnect theconduit 77 from the vacuum source 19 whereby the air will return notonly to the chamber 127 of the memory unit 79 through the opened valveseat 131 to de-activate the same, but also permit air to return to thechamber 127A of the nand unit 82 whereby the compression spring 130A ofthe nand" unit 82 will move the diaphragm member 117A upwardly to closethe valve seat 131A and open the valve seat 133A so that the chambers 45and 45 and the actuators 40 and 40' will be interconnected to theatmosphere by the passage means 132A in the diaphragm member 117Aleading to the chamber 126A that is intercon' nected to the open valveseat 123A that leads to the atmosphere at the port 108 as well as by thebleed means 100 in the conduit 104. Similarly, the diaphragm member 117of the memory" unit 79 moves downwardly in FIG. 2 under the force of thecompression spring 130 because the chamber 127 returns to atmosphericcondition so that the valve seat 131 is now closed and the valve seat133 is opened to return the chamber 126 to atmospheric condition.

Since flames do not now exist at the main burner means 12, the ignitiontemperature sensing means 63 now causes the valve member 65 to move awayfrom the valve seat 68 and against the valve seat 68' so that when thevalve member 73 of the thermostat 71 is again moved to its closedcondition against the valve seat 76 by the temperature effect in thedryer 11 falling below the set temperature effect of the thermostat 71,the main burner means 12 will be operated in the manner previouslydescribed wherein the igniter means 47 will again be first energized toignition condition before the valve members l4 and 14 can be opened.

However, if during the normal operation of the control system 10,wherein the main burner means 12 has been interconnected to the fuelsource 13 in the manner previously described so as to be continuouslyburning, the housewife or the like should open the dryer doortemporarily to cause the switch blades 29 and 29 to open so as todisconnect the electric motor 15 from the power source leads L and Lwhereby the vacuum source 19 ceases to function so that the controlsystem bleeds to atmospheric condition by the controlled bleed 100, andthe housewife subsequently closes the dryer door to again activate themotor 15 before the ignition temperature sensing means 63 has moved thevalve member 65 away from the valve seat 68, the nand unit 82 cannotcause reopening of the valve means 14 and 14' because the memory" unit79 has not been reset to its activated position so as to interconnectthe conduit 77 to the chamber 122 thereof and, thus, to the chamber 127Aof the nand unit 82 as it requires an opening of the valve member 65away from the valve seat 68 of the ignition temperature sensing means 63to activate the memory" unit 79 and the nand" unit 82 requires asubsequent closing of the valve member 65 against the valve seat 68 toterminate the vacuum signal to the chamber 123A thereof before the nand"unit 82 can be activated to cause opening of the valve means 14 and 14.

Thus, it can be seen that the control system 10 of this inventionutilizes only two logic units each formed of identical structure butperforming different logic functions in a manner to control the mainburner means 12 so that the system requires that the ignition means 47be always pneumatically operated to ignition condition before the mainburner means 12 can be pneumatically operated to its on" condition eachtime there is a requirement to turn on the main burner means.

Further, it can be seen that the logic unit 79 of this invention is soconstructed and arranged that during the time of switching the memory"unit 79, no atmospheric signal is seen by the unit 79 to slow down orprevent its switching operation.

Further, any clogging of the restrictions 89 and 83 by dirt or the likeduring the operation of the system 10 will not cause an adversesituation as the bleed means will cause the valve means 14 and 14' toclose and thereby terminate the operation of the burner 12.

The details of the pneumatically operated valve means 14 and 14 of thisinvention will now be described and reference is now made to FIG. 3wherein it can be seen that the previously described pneumaticallyoperated valve means 14 and 14' are defined by the same housing means 35having the inlet 37 and outlet 38 formed therein and separated from eachother by the valve seats 36 and 36' in series with the outlet 38comprising an orifice having a tapering portion 200 and a cylindricalportion 201 to be controlled by the tapering end 202 of a metering pin203 normally urged to one flow rate position relative to the orifice 38by a compression spring 204 having one end 205 bearing against ashoulder 206 of the metering pin 203 and the other end 207 bearingagainst a shoulder means 208 of the housing 35.

The previously described valve members 39 and 39', tying means 44 and44' and flexible diaphragms 43 and 43' are respectively defined byflexible diaphragms 209 and 209' having their outer peripheries 210 and210 sealed to annular surfaces 211 and 21 1 of the housing means 35 bythe cup shaped housing members 41 and 41 previously described as thesame are fastened to the housing means 35 by suitable fastening means212 and 212' whereby the cup shaped housing members 41 and 41' cooperatewith the flexible diaphragms 209 and 209 to define the previouslydescribed chambers 45 and 45' adapted to be respectively disposed influid communication with the branch conduits and 105' through suitableopening means in the housing means 35 or cup shaped housing members 41and 41' as desired. The diaphragms 209 and 209' respectively havethickened central portionS which define valve members 213 and 213' foropening and closing the valve seats 36 and 36', the compression springs46 and 46' in the chambers 45 and 45 respectively tending to maintainthe valve members 213 and 213' against their respective valve seats 36and 36.

The housing means 35 has a stepped cylindrical passage 214 leading tothe valve seat 36 and being transversely intersected by the inlet 37.Fluid flow through the stepped cylindrical passage 214 to the valve seat36 is controlled by a pressure regulator generally indicated by thereference numeral 215 throughout the various figures in the drawings andcan be of any desired type.

However, the particular pressure regulator 215 illustrated in thedrawings is of the type that is fully disclosed and claimed in Ser. No.643,170, filed June 2, 1967, now US Pat. No. 3,550,623, and Ser. No.740,150, filed June 26, 1968, such copending applications being assignedto the same assignee to whom this application is assigned and do notform a part of this invention. Therefore, only sufficient details of thepressure regulator structure 215 will now be described in order to fullyunderstand the features of this invention.

As illustrated in FIG. 3, the housing 35 carries a pair of flexiblediaphragms 216 and 217 respectively having their outer peripheries 218and 219 held in annular grooves 220 and 221 of the housing means 35 bymetallic retainers 222 and 223, the retainer 223 also forming a closuremember. A valve stem 224 has a portion 225 passing through an opening226 in the flexible diaphragm 216 while being coupled thereto by a sealmember 227, the part 225 being interconnected to the medial portion 228of the flexible diaphragm 217 so as to move in unison therewith. Thevalve stem 224 carries a valve member 229 at the lower end thereof forcooperating with a valve seat 230 defined by the stepped portion of thecylindrical passage 214, the valve stem 224 having suitable guide fins231 thereon for guiding movement of the valve stem 224 in thecylindrical passage 214. The valve stem 224 is hollow so as tointerconnect the enlarged part 232 of the passage 214 below the valveseat 230 thereof and above the valve seat 36 to a chamber 233 definedbetween the flexible diaphragms 216 and 217.

The metallic retainer 223 substantially closes 011 the upper end of thehousing 35 and has a tubular portion 234 being internally threaded at235 to receive a threaded adjusting member 236. A compression spring 237is disposed between the adjusting member 236 and the diaphragm 217 totend to urge the diaphragm 217 and, thus, the valve member 229downwardly in a direction to open the valve seat 230.

In this manner, the setting of the adjusting member 236 and, thus, theforce of the compression spring 237 will cause the pressure regulator215 to maintain the pressure of the fuel passing through the housing 35from the fuel source 13 to the burner means 12 to be maintained at thepressure setting of the device 236 in the manner fully disclosed in theaforementioned copending patent applications relating to the regulator215.

In particular, the pressure of the fuel in the part 232 below the valveseat 230 is conveyed to the chamber 233 between the diaphragms 216 and217 to act against the under side of the diaphragm 217 in opposing theforce of the compression spring 237 tending to move the diaphragm 217downwardly. Thus, when the fuel pressure in the part 232 of the housing35 exceeds the pressure setting, the same moves the diaphragm 217upwardly in opposition to the force of the compression spring 237 todecrease the amount of opening of the valve seat 230 whereby thepressure in the outlet portion 232 of the housing 35 drops accordingly.Conversely, if the fuel pressure in the part 232 of the housing fallsbelow the pressure setting of the regulator 215, the force of thepressure in the chamber 233 has decreased so that the compression spring237 moves the flexible diaphragm 217 downwardly to increase the amountof opening of the valve seat 230 so that the pressure in the part 232 ofthe housing 35 can be increased.

In order to guide opening and closing movement of the valve members 213and 213' relative to their respective valve seats 36 and 36', the valvemembers 213 and 213' carry guide extensions 238 and 238 that projectthrough the valve seats 36 and 36' so as to guide open and closingmovement of the valve members 213 and 213' without restricting the flowthrough the valve seats 36 and 36.

The guide member 238' of the valve member 213' carries a lost motionmeans generally indicated by the reference numeral 239 forinterconnecting the valve member 213' to the metering pin 203 so as tocontrol movement thereof when the lost motion means 239 is fully takenup in a manner hereinafter described.

In particular, the lost motion means 239 comprises a substantially cupshaped member 240 telescoped over the enlarged upper end 241 of themetering pin 203 so that the under surface 242 of the enlarged head 241of the metering pin 203 is normally spaced above an annular shouldermeans 243 of the cup shaped member 240 when the valve member 213 isdisposed in its closed position against the valve seat 36' asillustrated in FIG. 3. However, when the chamber 45 is evacuated bybeing interconnected to a vacuum source, the diaphragm 209' is pulledupwardly in opposition to the force of the compression spring 46 and thevalve member 213' opens relative to the valve seat 36' and will notcause movement of the metering pin 203 relative to the orifice 38 untilthe shoulder 243 of the lost motion cup member 240 abuts against theunder surface 242 of the enlarged head 241 of the metering pin 203 tomove the same upwardly relative to the orifice 38 in opposition to theforce of the compression spring 204 as illustrated in FIG. 4 wherebywhen the diaphragm 209' is disposed in the full up position thereof asillustrated in FIG. 4, the metering pin 203 is now provided a greaterfuel flow rate through the orifice 38 than when in the normal positionillustrated in FIG. 3.

Accordingly, upon the opening of the valve member 213', if the same isonly opened relative to the valve seat 36' a distance sufficient toprevent movement of the metering pin 203 from the position illustratedin FIG. 3 to the position illustrated in FIG. 4, the pneumaticallyoperated valve means 14 and 14' of this invention will provide fuel flowto the burner means 12 at the flow rate level provided by the meteringpin 203 in its position as illustrated in FIG. 3. However, if the vacuumlevel being interconnected to the chamber 45' is increased so as tocause the diaphragm 209 to further move upwardly to the positionillustrated in FIG. 4 and carry the metering pin 203 therewith to theposition illustrated in FIG. 4, an increased fuel flow level will beprovided by the valve means 14 and 14 of this invention for the burnermeans 12.

Accordingly, the branch conduit as illustrated in FIGS. 1 and 2 can havea selector means 244 therein for controlling the degree of vacuum beingdirected to the chamber 45' so that at one setting of the selector 244,the interconnection of the vacuum source to the chamber 45 by thecontrol system 10 in the manner previously described will only cause thediaphragm 209' to move to an intermediate position thereof for openingthe valve seat 36 without causing movement of the meterinG pin 203 fromthe position illustrated in FIG. 3. The other setting of the selectormeans 244 will permit full vacuum to be interconnected to the chamber 45so that the diaphragm 209' will move the position illustrated in FIG. 4for providing a high flow rate to the burner means 12.

Therefore, it can be seen that when the control system 10 interconnectsthe vacuum source to the branch conduits 105 and 105' in the mannerpreviously described, the diaphragms 209 and 209' cause the valvemembers 213 and 213 to open away respectively from the valve seats 36and 36 so that the fuel source 13 can be interconnected to the burnermeans 12 and can have the pressure thereof regulated by the pressureregulator 215 whereby not only are improved pneumatically operated valvemeans provided by this invention, but also an improved pneumatic controlsystem utilizing such pneumatically operated valve means is provided bythis invention.

While the pneumatically operated valve means 14 and 14' of FIGS. 3 and 4have been described as having the valve member 213' thereof moved todifferent positions by having the pneumatic source level directedthereto provided by two different settings to provide high and low flamefuel flows to the burner means 12, another valve means of this inventioncan be utilized for providing such two fuel flow levels by utilizing thesame vacuum source in a selective manner.

Accordingly, reference is now made to FIG. wherein another housing means35A of this invention carrying two pneumatically operated valve means14A and 14'A is provided whereby parts similar to the pneumaticallyoperated valve means 14 and 14 previously described and illustrated areindicated by like reference numerals followed by the reference letter A.

As illustrated in FIG. 5, the housing means 35A is not provided with apressure regulator 215 between the inlet 37A thereof and the valve seat36A but the same could be provided with such a pressure regulator 215,if desired. The valve members 213A and 213'A as well as the metering pin203A are identical in their operation and structure previously describedexcept that the housing means 35A is so constructed and arranged thatthe same defines not only the chamber 45'A for the flexible diaphragm209A, but also defines another chamber 245 separated from the chamber45'A by a flexible diaphragm 246 having its outer periphery 247 disposedbetween the cup shaped housing member 41A and another cup shaped housingmember 247 while spanning an opening 248 in the closed end wall 249 ofthe first cup shaped housing member 41'A. A spring retainer 259 issubstantially cup shaped and is disposed in the opening 248 while havingan outer annular flange 250 thereof disposed between the flexiblediaphragm 246 and the end wall 259 of the cup shaped housing member4l'A, the cup shaped spring retainer 259 receiving the compressionspring 46'A therein which normally tends to urge the valve member 213Aagainst the valve seat 36'A as illustrated in FIG. 5. The flexiblediaphragm 246 is normally urged to the position illustrated in FIG. 5 bya compression spring 251 disposed in the chamber 245.

Thus, when the vacuum source is only interconnected to the chamber 45Ain the manner previously described, the flexible diaphragm 209'A movesupwardly and bottoms out against the spring retainer 259 before suchopening movement of the valve member 213'A will cause upward movement ofthe metering pin 203A. Thus, by merely interconnecting the vacuum sourceto the chamber 45A, the valve seat 36'A willbe fully opened but themetering pin 203A will merely provide a low fuel flow rate to the burnermeans 12 as the same remains in the position illustrated in FIG. 5. Ifit is desired to provide a higher fuel flow rate through the orifice38A, the vacuum source is additionally interconnected to the chamber 245whereby the flexible diaphragm 246 is moved upwardly in opposition tothe force of the compression spring 251 whereby the spring retainer 259also moves upwardly therewith and permits the flexible diaphragm 209'Ato further move upwardly to another open position thereof whereby thelost motion means 239A has been taken up and the metering pin 203A ismoved upwardly with the valve member 213'A to a new position thereof forproviding a high fuel flow rate to the burner means in a manner similarto the metering pin 203 previously described.

Therefore, it can be seen that this invention not only provides animproved pneumatically operated valve means for fuel burning apparatusor the like, but also this invention provides improved fuel controlsystems utilizing such pneumatically operated valve means.

While the form of this invention now preferred has been described asrequired by the statutes, other forms may be used all coming within thescope of the claims which follow.

What is claimed is:

1. A pneumatically operated valve meanS comprising a housing meanshaving an inlet separated from an outlet by a valve seat, said outlethaving an orifice through which the entire flow from said inlet mustpass when said valve seat is opened, a pneumatically operated valvemember being carried by said housing means for opening and closing saidvalve seat, and a metering pin having one end cooperating with saidorifice for controlling flow therethrough and being interconnected tosaid valve member so that said valve member and said metering pin areremovable as a self-contained unit from said housing means, saidmetering pin being interconnected to said valve member by lost motionmeans whereby said valve member can move to at least one open positionthereof without causing movement of said metering pin relative to saidorifice.

2. A pneumatically operated valve means as set forth in claim 1 whereinsaid lost motion means causes said metering pin to move relative to saidorifice when said valve member moves to another open position thereof.

3. A pneumatically operated valve means as set forth in claim 2 whereinsaid pneumatically operated valve member defines chamber means with saidhousing means whereby said chamber means is adapted to be interconnectedto a pneumatic source means for operating said valve member.

4. A pneumatically operated valve means as set forth in claim 1 whereinsaid valve member is adapted to provide two levels of flow through saidorifice by positioning said metering pin in accordance with movement ofsaid valve member.

5. A pneumatically operated valve means as set fOrth in claim 1 whereinanother pneumatically operated valve member is carried by said housingmeans for controlling a valve seat disposed between said first-namedvalve seat and said inlet.

6. A pneumatically operated valve means as set forth in claim 5 whereina pressure regulator is carried by said housing means for controllingthe degree of pressure of the fluid passing through said housing meansat a point in advance of said other valve seat.

7. A pneumatically operated valve means comprising a housing meanshaving an inlet separated from an outlet by a valve seat, said outlethaving an orifice through which the entire flow from said inlet mustpass when said valve seat is opened, a pneumatically operated valvemember being carried by said housing means for opening and closing saidvalve seat, and a metering pin having one end cooperating with saidorifice for controlling flow therethrough and being operativelyinterconnected to said valve member, said metering pin beinginterconnected to said valve member by lost motion means whereby saidvalve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to a pneumatic source means for operating said valvemember, said chamber means being adapted to cause said valve member tomove to said one open position thereof when said pneumatic source meansis at one level thereof and being adapted to cause said valve member tomove to said other open position thereof when said pneumatic sourcemeans is at another level thereof.

8. A pneumatically operated valve means comprising a housing meanshaving an inlet separated from an outlet by a valve seat, said outlethaving an orifice through which the entire flow from said inlet mustpass when said valve seat is opened, a pneumatically operated valvemember being carried by said housing means for opening and closing saidvalve seat, and a metering pin having one end cooperating with saidorifice for controlling flow therethrough and being operativelyinterconnected to said valve member, said metering pin beinginterconnected to said valve member by lost mofion means whereby saidvalve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to a pneumatic source meanS for operating said valvemember, said chamber means comprising two chambers, one of said chambersbeing adapted to cause said valve member to move to said one openposition thereof when said pneumatic source means is interconnected toonly that one chamber whereas said chambers are adapted to cause saidvalve member to move to said other open position thereof when saidpneumatic source means is interconnected to both chambers.

9. A pneumatically operated valve means as set forth in claim 8 whereina flexible diaphragm is carried by said housing means and separates saidtwo chambers from each other, a spring retainer cooperating with saiddiaphragm to move in unison therewith, and spring means disposed betweensaid retainer and said valve member to tend to move said valve member inone direction relative to said valve seat.

10. In a fuel control system having a source of fuel, a burner means anda pneumatic source means, the improvement comprising a pneumaticallyoperated valve means having a housing means provided with an inletseparated from an outlet by a valve seat, means interconnecting saidfuel source to said inlet, means interconnecting said burner means tosaid outlet, said outlet having an orifice through which the entire fuelflow from said inlet must pass when said valve seat is opened, apneumatically operated valve member being carried by said housing meansfor opening and closing said valve seat, and a metering pin having oneend cooperating with said orifice for controlling fuel flow therethroughand being interconnected to said valve member so that said valve memberand said metering pin are removable as a self-contained unit from saidhousing means, said metering pin being interconnected to said valvemember by lost motion means whereby said valve member can move to atleast one open position thereof without causing movement of saidmetering pin relative to said oriface.

11. In a fuel control system as set forth in claim 10, the furtherimprovement wherein said lost motion means causes said metering pin tomove relative to said orifice when said valve member moves to anotheropen position thereof.

12. In a fuel control system as set forth in claim 10, the furtherimprovement wherein said valve member is adapted to provide two levelsof fuel flow through said orifice by positioning said metering pin inaccordance with movement of said valve member.

13. In a fuel control system. as set forth in claim 10, the furtherimprovement wherein another pneumatically operated valve member iscarried by said housing means for controlling a valve seat disposedbetween said first-named valve seat and said inlet.

14. In a fuel control system as set forth in claim 13, the furtherimprovement wherein a pressure regulator is carried bysaid housing meansfor controlling the degree of pressure of the fuel passing through saidhousing means at a point in advance of said other valve seat.

15. In a fuel control system having a source of fuel, a burner means anda pneumatic source means, the improvement comprising a pneumaticallyoperated valve means having a housing means provided with an inletseparated from an outlet by a valve seat, means interconnecting saidfuel source to said inlet, means interconnecting said bumer means tosaid outlet, said outlet having an orifice through which the entire fuelflow from said inlet must pass when said valve seat is opened, apneumatically operated valve member being carried by said housing meansfor opening and closing said valve seat, and a metering pin having oneend cooperating with said orifice for controlling fuel flow therethroughand being operatively interconnected to said valve member, said meteringpin being interconnected to said valve member by lost motion meanswhereby said valve member can move to at least one open position thereofwithout causing movement of said metering pin relative to said orifice,said lost motion means causing said metering pin to move relative tosaid orifice when said valve member moves to another open positionthereof, said pneumatically operated valve member defining chamber meanswith said housing means whereby said chamber means is adapted to beinterconnected to said pneumatic source means for operating said valvemember.

16. In a fuel control system having a source of fuel, a burner means anda pneumatic source means, the improvement comprising a pneumaticallyoperated valve means having a housing means provided with an inletseparated from an outlet by a valve seat, means interconnecting saidfuel source to said inlet, means interconnecting said fuel source tosaid inlet, means interconnecting said burner means to said outlet, saidoutlet having an orifice through which the entire fuel flow from saidinlet must pass when said valve seat is opened, a pneumatically operatedvalve member being carried by said housing means for opening and closingsaid valve seat, and a metering pin having one end cooperating with saidorifice for controlling fuel fiow therethrough and being operativelyinterconnected to said valve member, said metering pin beinginterconnected to said valve member by lost motion means whereby saidvalve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to said pneumatic source means for operating said valvemember, said chamber means being adapted to cause said valve member tomove to said one open position thereof when said pneumatic source meansis at one level thereof and being adapted to cause said valve member tomove to said other open position thereof when said pneumatic sourcemeans is at another level thereof.

17. In a fuel control system having a source of fuel, a burner means anda pneumatic source means, the improvement comprising a pneumaticallyoperated valve means having a housing means provided with an inletseparated from an outlet by a valve seat, means interconnecting saidburner means to said outlet, said outlet having an orifice through whichthe entire fuel flow from said inlet must pass when said valve seat isopened, a pneumatically operated valve member being carried by saidhousing meanS for opening and closing said valve seat, and a meteringpin having one end cooperating with said orifice for controlling fuelflow therethrough and being operatively interconnected to said valvemember, said metering pin being interconnected to said valve member bylost motion means whereby said valve member can move to at least oneopen position thereof without causing movement of said metering pinrelative to said orifice, said lost motion means causing said meteringpin to move relative to said orifice when said valve member moves toanother open position thereof, said pneumatically operated valve memberdefining chamber means with said housing means whereby said chambermeans is adapted to be interconnected to said pneumatic source means foroperating said valve member, said chamber means comprising two chambers,one of said chambers being adapted to cause said valve member to move tosaid one open position thereof when said pneumatic source means isinterconnected to only that one chamber whereas said chambers areadapted to cause said valve member to move to said other open positionthereof when said pneumatic source means is interconnected to bothchambers.

18. In a fuel control system as set forth in claim 17, the furtherimprovementwherein a flexible diaphragm is carried by said housing meansand separates said two chambers from each other, a spring retainercooperating with said diaphragm to move in unison therewith, and springmeans disposed between said retainer and said valve member to tend tomove said valve member in one direction relative to said valve seat.

. a a s"

1. A pneumatically operated valve meanS comprising a housing meanshaving an inlet separated from an outlet by a valve seat, said outlethaving an orifice through which the entire flow from said inlet mustpass when said valve seat is opened, a pneumatically operated valvemember being carried by said housing means for opening and closing saidvalve seat, and a metering pin having one end cooperating with saidorifice for controlling flow therethrough and being interconnected tosaid valve member so that said valve member and said metering pin areremovable as a self-contained unit from said housing means, saidmetering pin being interconnected to said valve member by lost motionmeans whereby said valve member can move to at least one open positionthereof without causing movement of said metering pin relative to saidorifice.
 2. A pneumatically operated valve means as set forth in claim 1wherein said lost motion means causes said metering pin to move relativeto said orifice when said valve member moves to another open positionthereof.
 3. A pneumatically operated valve means as set forth in claim 2wherein said pneumatically operated valve member defines chamber meanswith said housing means whereby said chamber means is adapted to beinterconnected to a pneumatic source means for operating said valvemember.
 4. A pneumatically operated valve means as set forth in claim 1wherein said valve member is adapted to provide two levels of flowthrough said orifice by positioning said metering pin in accordance withmovement of said valve member.
 5. A pneumatically operated valve meansas set fOrth in claim 1 wherein another pneumatically operated valvemember is carried by said housing means for controlling a valve seatdisposed between said first-named valve seat and said inlet.
 6. Apneumatically operated valve means as set forth in claim 5 wherein apressure regulator is carried by said housing means for controlling thedegree of pressure of the fluid passing through said housing means at apoint in advance of said other valve seat.
 7. A pneumatically operatedvalve means comprising a housing means having an inlet separated from anoutlet by a valve seat, said outlet having an orifice through which theentire flow from said inlet must pass when said valve seat is opened, apneumatically operated valve member being carried by said housing meansfor opening and closing said valve seat, and a metering pin having oneend cooperating with said orifice for controlling flow therethrough andbeing operatively interconnected to said valve member, said metering pinbeing interconnected to said valve member by lost motion means wherebysaid valve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to a pneumatic source means for operating said valvemember, said chamber means being adapted to cause said valve member tomove to said one open position theReof when said pneumatic source meansis at one level thereof and being adapted to cause said valve member tomove to said other open position thereof when said pneumatic sourcemeans is at another level thereof.
 8. A pneumatically operated valvemeans comprising a housing means having an inlet separated from anoutlet by a valve seat, said outlet having an orifice through which theentire flow from said inlet must pass when said valve seat is opened, apneumatically operated valve member being carried by said housing meansfor opening and closing said valve seat, and a metering pin having oneend cooperating with said orifice for controlling flow therethrough andbeing operatively interconnected to said valve member, said metering pinbeing interconnected to said valve member by lost motion means wherebysaid valve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to a pneumatic source meanS for operating said valvemember, said chamber means comprising two chambers, one of said chambersbeing adapted to cause said valve member to move to said one openposition thereof when said pneumatic source means is interconnected toonly that one chamber whereas said chambers are adapted to cause saidvalve member to move to said other open position thereof when saidpneumatic source means is interconnected to both chambers.
 9. Apneumatically operated valve means as set forth in claim 8 wherein aflexible diaphragm is carried by said housing means and separates saidtwo chambers from each other, a spring retainer cooperating with saiddiaphragm to move in unison therewith, and spring means disposed betweensaid retainer and said valve member to tend to move said valve member inone direction relative to said valve seat.
 10. In a fuel control systemhaving a source of fuel, a burner means and a pneumatic source means,the improvement comprising a pneumatically operated valve means having ahousing means provided with an inlet separated from an outlet by a valveseat, means interconnecting said fuel source to said inlet, meansinterconnecting said burner means to said outlet, said outlet having anorifice through which the entire fuel flow from said inlet must passwhen said valve seat is opened, a pneumatically operated valve memberbeing carried by said housing means for opening and closing said valveseat, and a metering pin having one end cooperating with said orificefor controlling fuel flow therethrough and being interconnected to saidvalve member so that said valve member and said metering pin areremovable as a self-contained unit from said housing means, saidmetering pin being interconnected to said valve member by lost motionmeans whereby said valve member can move to at least one open positionthereof without causing movement of said metering pin relative to saidoriface.
 11. In a fuel control system as set forth in claim 10, thefurther improvement wherein said lost motion means causes said meteringpin to move relative to said orifice when said valve member moves toanother open position thereof.
 12. In a fuel control system as set forthin claim 10, the further improvement wherein said valve member isadapted to provide two levels of fuel flow through said orifice bypositioning said metering pin in accordance with movement of said valvemember.
 13. In a fuel control system as set forth in claim 10, thefurther improvement wherein another pneumatically operated valve memberis carried by said housing means for controlling a valve seat disposedbetween said first-named valve seat and said inlet.
 14. In a fuelcontrol system as set forth in claim 13, the further improvement whereIna pressure regulator is carried by said housing means for controllingthe degree of pressure of the fuel passing through said housing means ata point in advance of said other valve seat.
 15. In a fuel controlsystem having a source of fuel, a burner means and a pneumatic sourcemeans, the improvement comprising a pneumatically operated valve meanshaving a housing means provided with an inlet separated from an outletby a valve seat, means interconnecting said fuel source to said inlet,means interconnecting said burner means to said outlet, said outlethaving an orifice through which the entire fuel flow from said inletmust pass when said valve seat is opened, a pneumatically operated valvemember being carried by said housing means for opening and closing saidvalve seat, and a metering pin having one end cooperating with saidorifice for controlling fuel flow therethrough and being operativelyinterconnected to said valve member, said metering pin beinginterconnected to said valve member by lost motion means whereby saidvalve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to said pneumatic source means for operating said valvemember.
 16. In a fuel control system having a source of fuel, a burnermeans and a pneumatic source means, the improvement comprising apneumatically operated valve means having a housing means provided withan inlet separated from an outlet by a valve seat, means interconnectingsaid fuel source to said inlet, means interconnecting said fuel sourceto said inlet, means interconnecting said burner means to said outlet,said outlet having an orifice through which the entire fuel flow fromsaid inlet must pass when said valve seat is opened, a pneumaticallyoperated valve member being carried by said housing means for openingand closing said valve seat, and a metering pin having one endcooperating with said orifice for controlling fuel flow therethrough andbeing operatively interconnected to said valve member, said metering pinbeing interconnected to said valve member by lost motion means wherebysaid valve member can move to at least one open position thereof withoutcausing movement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to said pneumatic source means for operating said valvemember, said chamber means being adapted to cause said valve member tomove to said one open position thereof when said pneumatic source meansis at one level thereof and being adapted to cause said valve member tomove to said other open position thereof when said pneumatic sourcemeans is at another level thereof.
 17. In a fuel control system having asource of fuel, a burner means and a pneumatic source means, theimprovement comprising a pneumatically operated valve means having ahousing means provided with an inlet separated from an outlet by a valveseat, means interconnecting said burner means to said outlet, saidoutlet having an orifice through which the entire fuel flow from saidinlet must pass when said valve seat is opened, a pneumatically operatedvalve member being carried by said housing meanS for opening and closingsaid valve seat, and a metering pin having one end cooperating with saidorifice for controlling fuel flow therethrough and being operativelyinterconnected to said valve member, said metering pin beinginterconnected to said valve member by lost motion means whereby sAidvalve member can move to at least one open position thereof withoutcausing mOvement of said metering pin relative to said orifice, saidlost motion means causing said metering pin to move relative to saidorifice when said valve member moves to another open position thereof,said pneumatically operated valve member defining chamber means withsaid housing means whereby said chamber means is adapted to beinterconnected to said pneumatic source means for operating said valvemember, said chamber means comprising two chambers, one of said chambersbeing adapted to cause said valve member to move to said one openposition thereof when said pneumatic source means is interconnected toonly that one chamber whereas said chambers are adapted to cause saidvalve member to move to said other open position thereof when saidpneumatic source means is interconnected to both chambers.
 18. In a fuelcontrol system as set forth in claim 17, the further improvement whereina flexible diaphragm is carried by said housing means and separates saidtwo chambers from each other, a spring retainer cooperating with saiddiaphragm to move in unison therewith, and spring means disposed betweensaid retainer and said valve member to tend to move said valve member inone direction relative to said valve seat.